Background & Objective: Visceral leishmaniasis is a reticulo endothelia system and it is known as 'black fever' by Indians. According to WHO every year there are 500 thousand new cases of it in the world. The province of Ardabil, with 25-40% from all the country's leishmaniasis has a major part in the country and is considered as one of the main focuses in Iran. Due to its importance, this study was done to identify clinical signs and demographic characteristics of the patients.

 Methods: This was a descriptive cross-sectional study which was done retrospectively 110 children who were hospitalized in three different active hospitals between 1375-1382 entered in this study. Disease definition include parasite detection in bone marrow aspivation or special clinical signs (fever, spleenomegal, pansytopenia and weight loss) in addition direct agglutination test was positive. The samples were investigated in terms of demographic information. Place of living, clinical signs and the length of time between the symptoms of the disease and its diagnosis. To get to the results, simple descriptive statistics was used. 37.8% of the patients were diagnosed from the beginning of symptoms with in a month.

 Results: There were 56.4% boys and 43.6% girls of all the 110 children. DAT test was done in 97 patients which was positive in 91 cases (minimum positive titer ¹/₄₀₀). In 42 patients biopsy and bone marrow aspiration was done which was positive in 26 cases (lishman body detection). The age of the patients was 4 months -14 years. The most common findings were fever 97.3% and anorexia 97.1%. There was anemia in 90% thrombocytopenia in 60.8% and leukopenia in 24.8%. There was death in 6 patients (5.5%) and unresponsiveness to the treatment in 3 cases (2.7%).

 Conclusion: The results of the present study nearly corresponds to those of other studies. The main vulnerable community of visceral lieshmaniasis are mainly children. In order to decrease the mortality and morbidity its early diagnosis is essential. It is necessary that the physicians working in endemic regions be familiar enough with the disease.